The present invention relates to an elastically deformable insulating strip for a heat-insulated composite section with two metal rail sections and at least one insulating strip positioned between them and intended for windows, doors, or facades, wherein the insulating strip has a rectangular basic cross-section with anchoring webs along the edge that are accommodated on at least one side in recesses in the metal rail sections.
The recesses in the metal rail sections that accommodate the longitudinal-edge areas of the insulating strip have undercuts that the anchoring webs on the insulating strip engage behind.
The insulating strips must be inserted into the recesses in the metal rail sections when the composite section is assembled. The metal rail sections that are to be fastened together and the insulating strips are generally six meters long. The rail sections are cut to size without burrs at the end and the initial section of the recess that the insulating strip is threaded into is sharp-edged. Inserting the insulating strip rapidly into the corresponding undercut recess in the rail section requires a lot of skill on the part of the assembling personnel and the time required to insert the strip into the recess accounts for a lot of the assembly time.